Non-detachable fulcrum type liet tab for beverage container

ABSTRACT

A rigid bend is provided in rigid body of lift tab between nose and lift ends. The bending axis of rigid bend and fulcrum line are in a vertical plane. A flexible transition piece is integrally connected to rigid body so that nose end and lift end of rigid body are at same initial height about equal to container rim height. Various installation means for achieving such configuration are provided. The initial height of lift end provides a finger access at lift end to allow user to raise lift end from initial height to optimum height above container rim height without encountering resistant force. The optimum height allows user to properly grasp lift end with force for initiating an initial rupture of score line.

BACKGROUND OF THE INVENTION

Present invention relates to a non-detachable fulcrum type lift tab, and particularly to improving finger accessing and operating ability of the lift tab.

Non-detachable fulcrum type lift tab has been a standard device for opening a breakable section (i.e. tear panel) of top end wall of container for long time. After the tear panel being opened, lift tab and tear panel remains attached to top end wall. A long existing problem of fulcrum type lift tab is that it provides very limited under space for finger access. To lift up the tab, user must overcome the initial resistance from rupturing a score line of tear panel. This requires user to lift up the tab with force, but without proper finger grasping of the lift end. This opening method can be difficult or troublesome to some people.

In a conventional fulcrum type lift tab, the longitudinal axis is a straight line where the “nose end-to-fulcrum line” distance is much shorter than “lift end-to-fulcrum line” distance. When lift tab is rotated about fulcrum line to elevate the lift end, the nose end almost immediately makes contact with the top end wall of container, and thus stops rotation. Consequently, the height of lift end is restricted, which provides very limited under space.

In prior art, all attempts for solving the above problem can be summarized in the following categories:

(1). Provide an upward bend at lift end.

Since lift end must not exceed container rim height due to manufacturing and transportation concerns, this technique makes non-significant improvement to the problem. (See U.S. Pat. Nos. 3,967,752 and 5,653,335.)

(2). Provide a recessed area underneath lift end.

Since the depth of the recessed is also restricted due to manufacturing concern, this technique makes limited improvement to the problem. (See U.S. Pat. Nos. 5,653,355 and 6,138,856.)

(3). Provide a flexible recessed area underneath lift end.

The flexible recessed area is flexed upward during manufacturing. But, by pressing down lift tab against the recessed area, it is flexed downward to a concave shape for providing a finger access. This technique overcomes the drawback of the technique (2) above. However, it requires two step action to allow user to grasp the lift end. (See U.S. Pat. 7,168,586.)

(4). Provide a recessed area within tear panel underneath nose end.

This technique may effectively increase the height of lift end. However, the drawback is that the applied force at the recessed area does not effectively cause a shear rupture of score line. A portion of applied force is distributed to bending the tear panel about the score line. (See U.S. Pat. Nos. 5,385,254, 3,957,172 and 5,653,355.)

(5). Provide a secondary fulcrum line between nose end and fulcrum line.

This technique is equivalent to moving fulcrum line forward. Since “nose end-to-fulcrum line” distance is typically short, forward movement of fulcrum line is restricted. Consequently, this technique makes limited improvement to the problem. Manufacturing is also more complicated and costly. (See U.S. Pat. No. 5,007,554.)

(6). Provide an upwardly inclined nose section.

In U.S. Pat. No. 5,947,317, Hall proposes an upwardly inclined nose section. Lift section lies closely on top end wall of container without a finger access. To lift up the tab, user needs to press down the upwardly inclined nose section with a finger or thumb. This causes rotation of the lift tab that slightly lifts the opposite lift end. While maintaining pressure on nose section, user can then insert another finger beneath the elevated lift end of the tab. The drawbacks of this technique are: (1). There is no direct finger access to the lift end. (2). It requires two step action to allow user to grasp the lift end. (3). Since the nose section is relatively short and small, pressing down this section to elevate the lift end can be a difficult task. (4). It provides nose section contact rather than nose end contact to initiate shear rupture of score line. However, nose end contact is more desirable because it generates more effective concentrated force.

SUMMARY OF THE INVENTION

One object of present invention is to provide the lift end with an initial height for a direct finger access.

Another object of present invention is to allow user to raise the lift end from the initial height to an optimum height without encountering a resistant force. When lift end is at the optimum height, user can properly grasp the lift end with force to initiate an initial shear rupture of a small section of score line (i.e., venting).

Another object of present invention is to allow user to propagate shear rupture of the remaining section of score line after venting.

Another object of present invention is to create effective force for initiating shear rupture of score line.

Another object of present invention is to allow user to complete the entire opening operation by a single (finger-lifting) action.

Another object of present invention is to achieve all the above objects without interfering manufacturing process.

Another object of present invention is to achieve all the above objects without affecting the drinking ability of container.

Another object of present invention is to achieve all the above objects without affecting the stacking ability of container.

Another object of present invention is to provide reasonable methods for utilization in existing manufacturing facility.

In present invention, the elongated rigid body of lift tab is divided into a forward nose section and a rearward lift section, which are integrally jointed at a bend axis to form a rigid bend with a predetermined angle. The rigid body is integrally connected to a transition piece, which is fixedly connected to an integral rivet of the top end wall of container. The transition piece is divided into a forward transition section and a rearward transition section, which are integrally jointed to form the fulcrum line. The rearward transition section is fixedly connected the rivet immediately rearward to fulcrum line. Preferably, the rearward transition section is extended below rigid body. This provides nose end contact to generate more effective concentrated force for initiating rupture of score line.

The predetermined angle of rigid bend is determined by positioning both nose end and lift end at an initial height about equal to the container rim height. The container rim height is considered the maximum allowable height for lift end and nose end due to manufacturing concerns. Lift end is raised from initial height to optimum height by bending the transition piece about fulcrum line with minimum force, but without encountering resistant force from initiating the initial rupture of score line (i.e., “venting”)

One distinctive feature of present invention is that present invention achieves the above first two objects of present invention as described above. No prior art has achieved these two objects in a single lift tab.

Another distinctive feature of present invention is that present invention provides an alternative means of increasing both initial and optimum heights of lift end by slightly increasing container rim height

Another distinctive feature of present invention is that present invention provides nose end contact to generate more effective concentrated force for initiating shear rupture of score line.

Another distinctive feature of present invention is that “nose end -to-score line”, “nose end-to-fulcrum line” and “lift end-to-fulcrum line” distances of present invention remain the same as those of conventional lift tab. Therefore, effectiveness of shear rupturing of score line is not affected by present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective plan and cross sectional views of the lift tab of first preferred embodiments of present invention, in which, lift end is at initial height.

FIG. 2 is another perspective cross sectional view of the lift tab of first preferred embodiments of present invention, in which, lift end is at optimum height.

FIG. 3 is a perspective cross sectional views of the lift tab of second preferred embodiments of present invention, in which, lift end is at initial height.

FIG. 4 is another perspective cross sectional view of the lift tab of second preferred embodiments of present invention, in which, lift end is at optimum height.

DETAILED DESCRIPTION OF THE DRAWINGS

In FIG. 1 and FIG.2, an elongated rigid body 1 of lift tab is divided into a forward nose section 2 and a rearward lift section 3, which are integrally jointed at a bend axis 4 to form a rigid bend 5 with a first predetermined angle. The bend axis 4 is perpendicular to the longitudinal axis A-A of the rigid body 1. The rigid body 1 is integrally connected to and supported by a transition piece 7, which is fixedly connected to an integral rivet 8 of the top end wall 9 of container. The transition piece 7 is divided into a forward transition section 10 and a rearward transition section 11, which are integrally jointed to form the fulcrum line 6 of the lift tab. Fulcrum line 6 and bend axis 4 are parallel to each other in a vertical plane. The reward transition section 11 receives rivet 8 immediately rearward to fulcrum line 6. The forward transition section 10 is deformed into a rigid recessed form. The rearward transition section 11 is located below rigid body 1. More precisely, it is below the bottom surface 12 of the lower planar flange 13 of the rigid body 1.

In FIG. 1, the first predetermined angle at the rigid bend 5 is determined by positioning both nose end 14 and lift end 15 at an initial height about equal to the container rim height 16. The container rim height 16 is considered the maximum allowable height for lift end 15 and nose end 14 due to manufacturing concerns. The first embodiments of present invention can be provided in two different forms prior to installing the embodiments to top end wall 9. The configuration of FIG. 1 can be achieved by two different means during installation. The first means is applied in the case that rearward transition section 11 is provided relatively in parallel to reward lift section 3 prior to installation. The second means is applied in the case that a second predetermined angle is provided between rearward transition section 11 and rearward lift section 3 prior to installation, which is determined by maintaining nose end 14 and lift end 15 in a horizontal plane while maintaining rearward transition section 11 in another horizontal plane.

The first means consists of: First, place rearward lift section 3 on top of top end wall 9 to receive rivet 8. Second, clamp rivet 8. Third, press lift tab with a die until both nose end 14 and lift end 15 are in contact with flat bottom surface of die. Fourth, press lift tab with die until a bend is formed between forward transition section 10 and rearward transition section 11 along fulcrum line 7.

The second means consists of: First, provide a means of holding lift tab with nose end 14 and lift end 15 being in a horizontal plane when placing lift tab on top of top end wall 9 to receive rivet 8. Second, clamp rivet 8. The configuration of FIG. 1 is achieved after clamping rivet 8. It needs to be noticed that during clamping rivet 8, the deformed top end of rivet must not interfere or stress the forward transition section 10. Stressing the forward transition section can cause lift end 15 to rise above container rim height 16.

In FIG. 2, the lift end 15 is raised from initial height to optimum height by rotating the lift section 3 by a predetermined degree, which causes nose section 2 to rotate downward by the same degree, and nose end 14 to make contact with top end wall 9. This operation requires minimum force for bending transition piece 7 about fulcrum line 6, but without encountering resistance force from initiating an initial shear rupture of score line (not shown) in top end wall 9.

FIG. 3 and FIG. 4 show the second preferred embodiments of present invention. Second preferred embodiments is different from first preferred embodiments only in one aspect. In first preferred embodiments, rigid body is raised up slightly above top end wall in the vertical plane of bend axis of rigid body and fulcrum line. In second preferred embodiments, rigid body directly lies on top end wall in the vertical plane of bend axis of rigid body and fulcrum line.

In FIG. 3, nose end 17 and lift end 18 are at an initial height about equal to container rim height 19. The configuration of FIG. 3 can be achieved by two different means during installation. The first means is applied in the case that bottom surface 20 of rearward transition section 21 is provided flush to bottom surface 22 of rearward lift section 23 prior to installation, and the first means is identical to the first means for achieving configuration of FIG. 1 as described above. The second means is applied in the case that a predetermined angle is provided between rearward transition section 21 and reward lift section 23 prior to installation. The predetermined angle is determined by maintaining nose end 17 and lift end 18 in a horizontal plane while maintaining rearward transition section 21 in another horizontal plane. The second means is identical to the second means for achieving configuration of FIG. 1 as described above.

In FIG. 4, lift end 18 is at an optimum height above container rim height 19. The nose section 24 makes contact with top end wall 25 as opposite lift end 18 being raised to optimum height.

In present invention, an increase in container rim height allows the same increase in initial height, but much greater increase in optimum height. Therefore, it is advantageous to consider a small increase in container rim height as an alternative means of for improving the accessing and operating ability of lift tab.

The initial height of lift ends 15 and 18 (in FIG. 1 and FIG. 3 respectively) serves the purpose of providing lift end with a direct finger access, so that user can easily rotate lift section upward by a predetermined degree, and raise lift end from initial height to optimum height (in FIG. 2 and FIG. 4) with a minimum force, and without encountering resistance force from initiating a initial shear rupture of a small section of score line in top end wall.

The optimum height of lift ends 15 and 18 (in FIG. 2 and FIG. 4 respectively) serves the purpose of allowing lift end to be properly grasped by finger, so that user can exert a lifting force at lift end to cause nose end to initiate a shear rupture of a small section of score line for venting container internal pressure.

During venting operation, lift end is further lifted upward from optimum height to another higher level (not shown), where user is capable of exerting a relatively large force to propagate shear rupture of the remaining section of score line. This is contributed by the following facts: First, “nose end-to-score line” distance remains unchanged. Second, bending movement and nose end force remains unchanged regardless of lift end position.

After completion of rupturing the entire score line, the broken section of top end wall (i.e., tear panel) is hinged to end wall in a relatively vertical position within container, and lift end is restored to a final position (not shown) without interfering drinking ability of container. This is contributed by the following facts: First, the inclined angle of the nose section is relatively small. Second, final position of nose end can be adjusted to avoid any possible nose end interference with drinking ability.

From the above, it becomes apparent that the described embodiments meet all the objects of present invention. However, the described embodiments are not intended for limiting the scope of present invention. Variations and modifications are allowed within the scope of present invention. For example, various means can be adopted for positioning lift end and nose end at initial height during installation. For another example, various forms or shapes of forward nose section, reward lift section, and forward and rearward transition sections previously disclosed in prior art can adopted with technique of present invention, and are considered within the scope of present invention. 

1. A lift tab comprising of: an elongated rigid body being divided into a forward nose section and a rearward lift section which are integrally jointed at a bend axis to form a first rigid bend with a first predetermined angle, said bend axis being perpendicular to a longitudinal axis of said lift tab, said forward nose section having a nose end at its forward end, and said rearward lift section having a lift end at its rearward end; and a flexible transition piece being integrally connected to said rigid body, said transition piece being divided into a forward transition section and a rearward transition section which are integrally jointed at a fulcrum line perpendicular to said longitudinal axis of said lift tab, said forward transition section being deformed into a recessed rigid form, said rearward transition section being fixedly connected to an integral rivet of a top end wall of container immediately reward to said fulcrum line, said transition piece being only bendable about said fulcrum line; wherein: said bend axis of said rigid body and said fulcrum line being in parallel to each other in a nearly vertical plane; and a means being provided to allow said transition piece to position said lift and nose ends at a first initial height about equal to a container rim height; and said first initial height providing said lift end with a finger access, which allows an user to rotate said lift section upward by a second predetermined angle, to raise said lift end from said first initial height to a second optimum height, to rotate said nose section downward by said second predetermined angle, and to lower said nose end to a top surface of said top end wall with a minimum force for bending said transition piece about said fulcrum line, but without encountering resistance force from initiating an initial shear rupture of a small section of a score line in said top end wall; and said second optimum height providing said lift end with a finger grasping ability, which allows said user to exert a lifting force at said lift end, and to cause said nose end to initiate said initial shear rupture of said small section of said score line for venting internal pressure of said container.
 2. In claim 1, said rearward transition section is provided relatively in parallel to said rearward lift section below a bottom surface of said rearward lift section prior to installing said lift tab to said top end wall of said container, and said means for installing said lift and nose ends at said first initial height consists of: first, placing said rearward lift section on top of said top end wall to receive said rivet, second, clamping said rivet, third, pressing said lift tab with a die until both said nose and lift ends making contact with a flat bottom surface of said die, fourth, pressing said lift tab with die until a bend being formed between said forward and rearward transition sections along said fulcrum line.
 3. In claim 1, said rearward transition section is provided below a bottom surface of said rearward lift section, having a second predetermined angle formed between said rearward transition section and said rearward lift section prior to installing said lift tab to said top end wall of said container, in which said second predetermined angle is determined by maintaining said nose and lift ends in a horizontal plane while maintaining said rearward transition section in another horizontal plane, and said means for installing said lift and nose ends at said first initial height consists of: first, providing a means of holding said lift tab with said nose and lift ends being in a horizontal plane while placing said lift tab on top of said top end wall to receive said rivet, second, clamping said rivet.
 4. In claim 1, said rearward transition section is provided with a bottom surface flush to a bottom surface of said rearward lift section prior to installing said lift tab to said top end wall of said container, and said means for installing said lift and nose ends at said first initial height is identical to said means provided in claim
 2. 5. In claim 1, said rearward transition section is provided with a bottom surface flush to a bottom surface of said rearward lift section at forward ends of said rearward transition section and rearward lift section, having a second predetermined angle formed between said rearward transition section and said rearward lift section prior to installing said lift tab to said top end wall of said container, in which said second predetermined angle is determined by maintaining said nose and lift ends in a horizontal plane while maintaining said rearward transition section in another horizontal plane, and said means for installing said lift and nose ends at said first initial height is identical to said means provided in claim
 3. 6. In claim 1, said second optimum height of said lift end is above said container rim height.
 7. In claim 1, an increase in said container rim height causes the same increase in said first initial height, and a much greater increase in said second optimum height, so that said increase in said container rim height provides an alternative means for improving the accessing and operating ability of said lift tab.
 8. In claim 1, said small section of said score line is located immediately forward to said rivet.
 9. In claim 1, said lift end is further raised upward from said second optimum height to a third height after completion of said initial rupture of said small section of said score line, and said third height also provides said lift end with finger grasping ability that allows said user to exert a relatively large force to propagate shear rupture of the remaining section of said score line.
 10. In claim 9, after completion of said propagation of shear rupture of said remaining section of said score line, a broken section of said top end wall is hinged to said top end wall in a relatively vertical position within said container, and said lift end is restored to a final position without interfering drinking ability of said container. 